Goffin sprung a huge surprise when he beat injury-stricken world No 1 Rafael Nadal in a three-set thriller.

It means Australian Open semi-finalist Dimitrov will tackle the Belgian in a top of the table clash in the Pete Sampras group.

I think the court conditions will really, really suit Dimitrov. But again, there have been question marks hanging over him finishing matches. It's a tough one to call, but I will go with Dimitrov

Annabel Croft

"Dimitrov leads their head to heads 3-1, but Goffin won their last encounter in three tight sets which makes this a tough match to call," said Croft.

"I though Goffin was absolutely sensational against Nadal. He's such a beautiful ball-striker and for somebody who is so slight he creates quite a lot of power and shot-making capabilities through the court. He also served with precision and pace.

"Both of them have the tendency to double fault at pretty key moments, but Dimitrov did incredibly well to come through an emotional match with Thiem.

"What has surprised me most so far this week is the players who have been making their debuts have really talked about playing here, which is quite a stadium to be playing your best tennis in because of the atmosphere.

"I think the court conditions will really, really suit Dimitrov. But again, there have been question marks hanging over him finishing matches. It's a tough one to call, but I will go with Dimitrov."

Everybody has been talking about Dimitrov being a superstar, but now is his moment

Greg Rusedski

Rusedski expects the match to go three sets, but is also edging Dimitrov's way in what could be another tight and tense encounter.

"It's going to be close but I feel it's Dimitrov's time to step up right now even though I was really impressed with Goffin," said former US Open finalist, Rusedski. "You can give the backhand side and return of serve to Goffin, but if you look at all the other categories, I would go for Grigor.

"Everybody has been talking about Dimitrov being a superstar, but now is his moment."

Thiem remains a potent force on his favoured clay but is yet to replicate that form on faster surfaces. On hard courts, he has beaten a top-10 opponent only once in 15 matches. He will face Spain's Pablo Carreno Busta, who steps in to complete Nadal's round-robin matches following his withdrawal - live only on Sky Sports.

"It definitely helps Thiem that he's already had one match on this court," said Croft. "For Carreno Busta, yes, he's had a great year, but Thiem will have that advantage."

Rusedski also feels the young Austrian will come through against the US Open semi-finalist, saying: "The experience of playing in this stadium should hold Thiem in good stead and keep him in the group."

Annabel Croft and Greg Rusedski were speaking to Sky Sports' Raz Mirza at The O2.

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